Curable polyurethanes

Abstract

Curable (per)fluoropolyether polyurethanes obtained by reaction in a first step of a) (per)fluoropolyether diols having a number average molecular weight from 2,000 to 5,000; with b) diisocyanates of formula OCN—R—NCO   (VIA) wherein R is a hydrogenated and/or fluorinated radical; in a second step with the compound c) saturated or unsaturated aliphatic hydrogenated diols, (alkyl)cycloaliphatic, aromatic; oligomers or polymers of butadiene with a number average molecular weight from 500 to 4,000 having end hydroxyl groups; provided that: when the diisocyanate b) is used and the radical R in formula (VIA) is: —Ph—CH 2 —Ph—, the hydrogenated diols c) are optional; when the radical R has a meaning different from that above mentioned, at least one of the used hydrogenated diols c) is selected from those belonging to the c 2 )-c 6 ) groups; the sum of the equivalents of the compounds a) and c) being equal to the equivalents of the compound b).

1. Cured manufactured articles obtained from compositions comprising:
 hydrogen-containing rubbers, 
 a curing agent, and 
 curable perfluoropolyether polyurethanes obtained by reaction among the following compounds 
 a) perfluoropolyether diols having a number average molecular weight from 2,000 to 5,000; 
 b) diisocyanates of formula
   OCN—R—NCO  (VIA) 
 
  wherein R is a hydrogen-containing and/or fluorinated radical; 
 c) hydrogen-containing diols selected from one or more of the following: 
 c 1 ) C 2 -C 12  aliphatic diols; 
 c 1A ) C 6 -C 18  (alkyl)cycloaliphatic or (alkyl)aromatic diols, optionally comprising in the molecule two aliphatic or aromatic rings having 6 carbon atoms; 
 c 2 ) unsaturated aliphatic diol having formula:
   HO—CH 2 —CHOH—(CH 2 ) nb —(O)— nb′ —CH═CH 2   (XII) 
 
  wherein nb is an integer from 1 to 12 and nb′ is an integer and is 0 or 1; 
 c 3 ) unsaturated aliphatic diol having formula:
   HO—(CH 2 ) v′ —CH═CH—(CH 2 ) v″ —OH  (XIII) 
 
  wherein v′ and v″ are numbers higher than 1, such that v′+v″ is a number comprised between 2 and 10; 
 c 4 ) butadiene oligomers or polymers having a number average molecular weight from 500 to 4,000 functionalized with terminal hydroxyl groups; 
 c 5 ) mono-glycerides of C 11 -C 24  fat acids containing at least one unsaturation; 
 c 6 ) trimethylolpropane monoallylether (TMPA):
   CH 3 —C(CH 2 OH) 2 —CH 2 OCH 2 —CH═CH 2   
 
 
       with the proviso that:
 when diisocyanate b) is used wherein R in formula (VIA) is different from —Ph—CH 2 —Ph—, at least one of the hydrogen-containing diols c) is used, selected from those belonging to the c 2 )-c 6 ) groups;
 the amount of the component a) in the final polyurethane being higher than 60% by weight, said polyurethanes being obtained by reacting component a) with b), and in a second step the reaction mixture with component c) to remove the —NCO excess, the sum of the equivalents of components a) and c) being equal to the equivalents of component b). 
 
 
     
     
       2. Cured manufactured articles according to  claim 1 , wherein in the polyurethanes the perfluoropolyether diols indicated in a) have one or more of the following units statistically distributed along the chain: (C 3 F 6 O); (CFYO) wherein Y is F or CF 3 ; (C 2 F 4 O); (CF 2 /CF 2 ) x′ CF 2 O) wherein x′ is an integer equal to 1 or 2; (CR 4 R 5 CF 2 CF 2 O) wherein R 4  and R 5  are equal to or different from each other and selected between H, Cl, and wherein one fluorine atom of the —CF 2  unit can optionally be substituted with H, Cl or (per)fluoroalkyl, having from 1 to 4 carbon atoms. 
     
     
       3. Cured manufactured articles according to  claim 2 , wherein in the polyurethanes the perfluoropolyether compounds a) are selected from the group consisting of the following with the perfluorooxyalkylene units statistically distributed along the chain:
   (a′): —CF 2 O—(CF 2 CF 2 O) p′ (CF 2 O) q′ —CF 2   (VIII) 
 
       wherein: p′ and q′ are numbers such that the q′/p′ ratio is comprised between 0.2 and 2 and the number average molecular weight is in the above indicated range for perfluoropolyether diols a);
   (b′): —CFY—O—(CF 2 CF(CF 3 )O) r′ —(CF 2 CF 2 O) s′ —(CFYO) t′ —CFY—  (IX) 
 
       wherein:
 Y is as defined in  claim 2 ; r′, s′ and t′ are numbers such that r′+s′ is in the range 1-50, the ratio t′/(r′-+s′) is in the range 0.01-0.05, r′+s′ being different from zero, and the molecular weight is in the above range for perfluoropolyether diols a);
   (c′): —CF(CF 3 )(OCFY) t′ (OC 3 F 6 ) u′ —OR′ f O—(C 3 F 6 O) u′ (CFYO) t′ CF(CF 3 )—  (X) 
 
 
       wherein:
 R′ f  is a C 1 -C 8  perfluoroalkylene; u′+t′ is a number such that the number average molecular weight is in the range indicated for perfluoropolyether diols a); t′ can also be equal to zero; Y is as above;
   (d′): —CF 2 CF 2 O—(CF 2 (CF 2 ) x′ CF 2 O) v′ —CF 2 CF 2 —  (XI) 
 
 
       wherein:
 v′ is a number such that the molecular weight is in the range indicated for perfluoropolyether diols a), x′ is an integer equal to 1 or 2; and
   (e′): —CF 2 CH 2 —(OCF 2 CF 2 CH 2 ) w′ —OR′ f O—(CH 2 CF 2 CF 2 O) w′ —CH 2 CF 2   (XII) 
 
 
       wherein:
 R′ f  is as above; w′ is a number such that the number average molecular weight is in the range indicated above for perfluoropolyether diols a); the end groups of the perfluoropolyethers component a) being —CH 2 —(OCH 2 CH 2 ) k′ —OH, wherein k′ is a number comprised between 0 and 5. 
 
     
     
       4. Cured manufactured articles according to  claim 1 , wherein in the polyurethanes the diisocyanates b) are selected from the group consisting of:
 b 1 ) hydrogen-containing diisocyanates;
   OCN—R H —NCO  (VIA-1) 
 wherein R H  has the following meanings: 
 C 2 -C 12  aliphatic bifunctional radical; 
 C 6 -C 18  cycloaliphatic or alkylen-cycloaliphatic, wherein optionally the cycloaliphatic ring is substituted with one or more C 1 -C 3  alkyl groups; 
 C 6 -C 18  aromatic bifunctional radical, wherein the aromatic ring is substituted with one or more C 1 -C 3  alkyl groups, or R H  contains two aromatic rings, each having one —NCO group, linked by a C 1 -C 6  alkylene chain; and 
 
 b 2 ) fluorinated diisocyanates of general formula;
   OCN—R F-L —NCO  (VIB) 
 
  wherein R F-L  has the following meanings:
 aliphatic bifunctional radical having formula
   —(CH 2 ) g —(CF 2 ) g ′ —(CH 2 ) g —  (VIC) 
 
  wherein g is an integer and can be 1 or 2, g′ is an integer from 2 to 16; 
 C 14 -C 18  aromatic bifunctional radical containing two aromatic rings, each having one —NCO group, linked by C 2 -C 6  perfluoroalkylene chain; 
 
 
       excluding the diisocyanate b) wherein R H  in formula (VIA-1) is equal to
   —PH—CH 2 —PH—. 
 
     
     
       5. Cured manufactured articles according to  claim 4 , wherein in the polyurethanes the diisocyanates b) are hydrogen-containing. 
     
     
       6. Cured manufactured articles according to  claim 1 , wherein in the polyurethanes the diols c) are selected from the group consisting of: butandiol (BDO), butendiol (BDE), 1,2-propandiol (PDO), 3-allyloxy-1,2-propandiol (APDO), and trimethylolpropane monoallylether (TMPA). 
     
     
       7. Cured manufactured articles according to  claim 1 , wherein the polyurethanes comprise component b) wherein R of formula (VIA) is different from —Ph—CH 2 —Ph—, and component c) is selected from the unsaturated diols of the classes c 2 ) and/or c 6 ). 
     
     
       8. Cured manufactured articles according to  claim 1 , wherein in the polyurethanes the perfluoropolyether diols indicated in a) have a number average molecular weight from 2,500 to 4,000. 
     
     
       9. Cured manufactured articles according to  claim 1 , wherein in the amount of the component a) in the final polyurethane is higher than 70% by weight. 
     
     
       10. Cured manufactured articles according to  claim 1 , wherein in the c 5 ) mono-glycerides are of C 14 -C 18  fat acids containing at least one unsaturation. 
     
     
       11. Curable compositions comprising hydrogen-containing rubbers, a curing agent and curable polyurethanes obtained by reaction among the following compounds:
 a) perfluoropolyether diols having a number average molecular weight from 2,000 to 5,000; 
 b) diisocyanates of formula
   OCN—R—NCO  (VIA) 
 
  wherein R is a hydrogen-containing and/or fluorinated radical; 
 c) hydrogen-containing diols selected from one or more of the following: 
 c 1 ) C 2 -C 12  aliphatic diols; 
 c 1A ) C 6 -C 18  (alkyl)cycloaliphatic or (alkyl)aromatic diols, optionally comprising in the molecule two aliphatic or aromatic rings having 6 carbon atoms; 
 c 2 ) unsaturated aliphatic diol having formula:
   HO—CH 2 —CHOH—(CH 2 ) nb —(O)— nb′ —CH═CH 2   (XII) 
 
  wherein nb is an integer from 1 to 12 and nb′ is an integer and is 0 or 1; 
 c 3 ) unsaturated aliphatic diol having formula:
   HO—(CH 2 ) v′ —CH═CH—(CH 2 ) v″ —OH  (XIII) 
 
  wherein v′ and v″ are numbers higher than 1, such that v′+v″ is a number comprised between 2 and 10; 
 c 4 ) butadiene oligomers or polymers having a number average molecular weight from 500 to 4,000 functionalized with terminal hydroxyl groups; 
 c 5 ) mono-glycerides of C 11 -C 24  fat acids containing at least one unsaturation; 
 c 6 ) trimethylolpropane monoallylether (TMPA):
   CH 3 —C(CH 2 OH) 2 —CH 2 OCH 2 —CH═CH 2   
 
 
       with the proviso that:
 when diisocyanate b) is used wherein R in formula (VIA) is different from —Ph—CH 2 —Ph—, at least one of the hydrogen-containing diols c) is used, selected from those belonging to the c 2 )-c 6 ) groups;
 the amount of the component a) in the final polyurethane being higher than 60% by weight, said polyurethanes being obtained by reacting component a) with b), and in a second step the reaction mixture with component c) to remove the —NCO excess, the sum of the equivalents of components a) and c) being equal to the equivalents of component b). 
 
 
     
     
       12. Curable compositions according to  claim 11 , wherein in the polyurethanes the perfluoropolyether diols indicated in a) have one or more of the following units statistically distributed along the chain: (C 3 F 6 O); (CFYO) wherein Y is F or CF 3 ; (C 2 F 4 O); (CF 2 (CF 2 ) x′ CF 2 O) wherein x′ is an integer equal to 1 or 2; (CR 4 R 5 CF 2 CF 2 O) wherein R 4  and R 5  are equal to or different from each other and selected between H, Cl, and wherein one fluorine atom of the —CF 2  unit can optionally be substituted with H, Cl or (per)fluoroalkyl, having from 1 to 4 carbon atoms. 
     
     
       13. Curable compositions according to  claim 12 , wherein in the polyurethanes the perfluoropolyether compounds a) are selected from the group consisting of the following with the perfluorooxyalkylene units statistically distributed along the chain:
   (a′): —CF 2 O—(CF 2 CF 2 O) p′ (CF 2 O) q′ —CF 2   (VIII) 
 
       wherein:
 p′ and q′ are numbers such that the q′/p′ ratio is comprised between 0.2 and 2 and the number average molecular weight is in the above indicated range for perfluoropolyether diols a);
   (b′): —CFYO—(CF 2 CF(CF 3 )O) r′ —(CF 2 CF 2 O) s′ —(CFYO) t′ —CFY—  (IX) 
 
 
       wherein:
 Y is F or CF 3 ; r′, s′ and t′ are numbers such that r′+s′ is in the range 1-50, the ratio t′/(r′-+s′) is in the range 0.01-0.05, r′+s′ being different from zero, and the molecular weight is in the above range for perfluoropolyether diols a);
   (c′): —CF(CF 3 )(OCFY) t′ (OC 3 F 6 ) u′ —OR′ f O—(C 3 F 6 O) u′ (CFYO) t′ CF(CF 3 )—  (X) 
 
 
       wherein:
 R′ f  is a C 1 -C 8  perfluoroalkylene; u′+t′ is a number such that the number average molecular weight is in the range indicated for perfluoropolyether diols a); t′ can also be equal to zero; Y is as above;
   (d′): —CF 2 CF 2 O—(CF 2 (CF 2 ) x′ CF 2 O) v′ —CF 2 CF 2 —  (XI) 
 
 
       wherein:
 v′ is a number such that the molecular weight is in the range indicated for perfluoropolyether diols a), x′ is an integer equal to 1 or 2; and
   (e′): —CF 2 CH 2 —(OCF 2 CF 2 CH 2 ) w′ —OR′ f O—(CH 2 CF 2 CF 2 O) w′ —CH 2 CF 2   (XII) 
 
 
       wherein:
 R′ f  is as above; w′ is a number such that the number average molecular weight is in the range indicated above for perfluoropolyether diols a); the end groups of the perfluoropolyether component a) being —CH 2 —(OCH 2 CH 2 ) k ′ —OH, wherein k′ is a number comprised between 0 and 5. 
 
     
     
       14. Curable compositions according to  claim 11 , wherein in the polyurethanes the diisocyanates b) are selected from the following:
 b 1 ) hydrogen-containing diisocyanates;
   OCN—R H —NCO  (VIA-1) 
 wherein R H  has the following meanings: 
 C 2 -C 12  aliphatic bifunctional radical; 
 C 6 -C 18  cycloaliphatic or alkylen-cycloaliphatic, wherein optionally the cycloaliphatic ring is substituted with one or more C 1 -C 3  alkyl groups; 
 C 6 -C 18  aromatic bifunctional radical, wherein the aromatic ring is substituted with one or more C 1 -C 3  alkyl groups, or R H  contains two aromatic rings, each having one —NCO group, linked by a C 1 -C 6  alkylene chain; and 
 
 b 2 ) fluorinated diisocyanates of general formula;
   OCN—R F-L —NCO  (VIB) 
 
  wherein R F-L  has the following meanings:
 aliphatic bifunctional radical having formula
   —(CH 2 ) g —(CF 2 ) g ′ —(CH 2 ) g —  (VIC) 
 
  wherein g is an integer and can be 1 or 2, g′ is an integer from 2 to 16; 
 C 14 -C 18  aromatic bifunctional radical containing two aromatic rings, each having one —NCO group, linked by C 2 -C 6  perfluoroalkylene chain; 
 
 
       excluding the diisocyanate b) wherein R H  in formula (VIA-1) is equal to
   —PH—CH 2 —PH—. 
 
     
     
       15. Curable compositions according to  claim 14 , wherein in the polyurethanes the diisocyanates b) are hydrogen-containing. 
     
     
       16. Curable compositions according to  claim 11 , wherein in the polyurethanes the diols c) are selected from the group consisting of: butandiol (BDO), butendiol (BDE), 1,2-propandiol (PDO), 3-allyloxy-1,2-propandiol (APDO), and trimethylolpropane monoallylether (TMPA). 
     
     
       17. Curable compositions according to  claim 11 , comprising component a), component b) wherein R of formula (VIA) is different from —Ph—CH 2 —Ph—, and component c) is selected from the unsaturated diols of the classes c 2 ) and/or c 6 ). 
     
     
       18. Curable compositions according to  claim 11 , wherein the ratio by weight between the polyurethanes and the hydrogen-containing rubber is from 0.3:100 to 50:100. 
     
     
       19. Curable compositions according to  claim 11 , wherein in the polyurethanes the perfluoropolyether diols indicated in a) have a number average molecular weight from 2,500 to 4,000. 
     
     
       20. Curable compositions according to  claim 11 , wherein in the c 5 ) mono-glycerides are of C 14 -C 18  fat acids containing at least one unsaturation. 
     
     
       21. Curable compositions according to  claim 11 , wherein in the amount of the component a) in the final polyurethane is higher than 70% by weight. 
     
     
       22. Curable compositions according to  claim 18 , wherein the ratio by weight between the polyurethanes and the hydrogen-containing rubber is from 1:100 to 15:100.